1. Field of the Invention
This invention relates, generally, to allografts. More specifically, it relates to an apparatus and method for fabricating bone grafts from cortical segments.
2. Brief Description of the Prior Art
The procedure of allotransplantation is known in the art for effectively transplanting tissue from one individual (donor) to another individual (recipient) of the same species. In particular, bone grafts are used to replace or enhance bones of individuals whose own bones have degenerated or have become damaged through injury. Further, cortical and lumbar allografts are often used in spinal fusions, or other orthopedic procedures for the replacement of bone tissue.
Often, cortical allografts are utilized in the cervical region of a spine (i.e., during cervical spinal fusions, corpectomies, etc.), and lumbar allografts are utilized in the lumbar region of the spine (i.e., lumbar spinal fusions, corpectomies, etc.). However, each cortical allograft ring or wedge is quite costly (well over $1,000 per ring or wedge used per level on a single patient with a patient potentially having as many as four (4) levels performed during a surgery), and as such, that cost is typically passed on to the patient. Different types of pre-cut cortical allograft rings or wedges are needed by different patients and are thus purchased by the healthcare institutions based on needs of the patients.
Healthcare institutions have attempted to lower this cost by purchasing cortical struts or segments that can be manually cut to create the appropriately sized rings or wedges. Cutting these cortical struts typically involves various hand instruments, such as bone-cutting shears/scissors, osteotomes, bone-cutting saw blades and the like. However, manually forming these bone grafts from cortical struts is very time-consuming and requires significant effort before or during a surgical procedure where time and money are important commodities.
Tabletop apparatuses used fir cutting and fabricating bone grafts are known in the art, though each has its own limitations or drawbacks that are overcome by the current invention. For example, U.S. Pat. Nos. 6,648,894 and 7,736,366 to Abdelgany et al. describe an apparatus and method for guiding and forming a bone graft. The apparatus/guide includes a holding mechanism to hold the graft material in place and a pattern that corresponds to the pattern desired for the shape of the bone graft. The guide can further include a cutting guide with a pattern desired for the shape of the bone graft. However, utilizing this apparatus and the methodology taught therein, a surgical team would need to expend an excess amount of time and effort forming a single bone graft, where time and effort are very important considerations for overall cost and time of the surgical procedure.
U.S. Pat. No. 6,962,592 to Gatturna et al. describes an apparatus for cutting allograft bone implants from donor bone. The donor bone is placed on a flat surface, and pneumatic cylinders with blades are lowered to cut the bone in order to form allograft bone implants. However, this apparatus requires several automated moving parts and would be difficult to manufacture and use. This requires excess time and effort to be expended by the surgical team, along with increased possibility of machine malfunction.
U.S. Pat. No. 7,699,851 to Dalton relates to a bone cutting jig system for spinal implant procedures. The system requires two separate cutting jigs. In the first cutting jig, two cutting guides are disposed in bi-convex configuration, and the surgical team must operate a uniquely designed reciprocating saw against the cutting guides to cut the graft material. This would require excess time and energy to be expended by the surgical team, along with an additional skill needed by the surgical team to make the appropriate cuts. Additionally, the biconvex configuration of the cutting guides would fail to product bone grafts suitable for cervical allotransplantation.
U.S. Pat. No. 7,802,503 to Couvillion et al relates to an apparatus for preparing bone grafts, in particular grafts for lumbar/thoracic interbody fusion. The apparatus includes a bone holder connected to an arm that is hingedly coupled to one end of a base. On the other end of the base is a serrated surface. When a bone graft is to be cut, the bone holder hinges toward the base and serrated surface holding the bone against the serrated edge. The bone holder includes two cutting guides through which the surgical team must insert blades to cut and form the bone graft. This technology suffers from a few of the same issues seen in the '851 patent. The blades are not conducive for forming cervical allografts, and the apparatus requires an excess amount of manual effort and time to be expended. There are also many moving parts that can hinder the overall effectiveness and efficiency of the apparatus.
U.S. Pat. No. 8,127,646 to Couvillion et al. describes an apparatus for preparing bone grafts, in particular grafts for cervical interbody fusion, though quite similar to the '503 patent. The apparatus includes a bone holder connected to an arm that can be secured to one end of a base. On the other end of the base are a plurality of fingers. When a bone graft is to be cut, the bone holder is secured to the base such that the bone is held against the fingers. The bone holder includes its own set of fingers with a plurality of slots therebetween that line up with the fingers on the base. The slots in the bone holder are a guide as to where the surgical team would insert blades to cut and form the bone graft. Though this technology is intended to form cervical bone grafts, it suffers from similar issues to that seen in the '503 patent in that it requires an excess amount of manual effort and time to be expended.
Accordingly, what is needed is an apparatus that facilitates the efficient and accurate fabrication of cortical rings or wedges, in particular for cervical allotransplantation. However, in view of the art considered as a whole at the time the present invention was made, it was not obvious to those of ordinary skill in the field of this invention how the shortcomings of the prior art could be overcome.
All referenced patents are incorporated herein by reference in their entireties. Furthermore, where a definition or use of a term in a reference, which is incorporated by reference herein, is inconsistent or contrary to the definition of that term provided herein, the definition of that term provided herein applies and the definition of that term in the reference does not apply.
While certain aspects of conventional technologies have been discussed to facilitate disclosure of the invention, Applicants in no way disclaim these technical aspects, and it is contemplated that the claimed invention may encompass one or more of the conventional technical aspects discussed herein.
The present invention may address one or more of the problems and deficiencies of the prior art discussed above. However, it is contemplated that the invention may prove useful in addressing other problems and deficiencies in a number of technical areas. Therefore, the claimed invention should not necessarily be construed as limited to addressing any of the particular problems or deficiencies discussed herein.
In this specification, where a document, act or item of knowledge is referred to or discussed, this reference or discussion is not an admission that the document, act or item of knowledge or any combination thereof was at the priority date, publicly available, known to the public, part of common general knowledge, or otherwise constitutes prior art under the applicable statutory provisions; or is known to be relevant to an attempt to solve any problem with which this specification is concerned.